Introduction. The article presents the ontological aspect of fantasy as a form of scientific knowledge. The concept of the role of normative scientific and cognitive structures and creative cognitive potential, which has ontological roots, in scientific knowledge is being developed. The study is conducted using works on the history and philosophy of science. The focus is on factors that are immanent to science and external to it, capable of not only influencing scientific activity, but also leading to a change in the types of rationality.
